This invention relates to flapper type valve closures for toilet tanks generally; and, in particular, to a flapper valve containing a novel internal ball check valve that allows the user to select whether the entire tank volume shall be emptied or, a preselected smaller volume.
The prior art discloses numerous types and variations of flapper flush valves. The majority of these prior art valves are constructed of a flexible elastomer to provide a hinge action and have a flat sealing ring area surrounding a hollow buoyancy chamber. The valves are opened by a chain and, once opened, remain open until the liquid level in the tank drops to a level approximately that of the buoyant chamber. From that point on, the valve with its flat sealing ring drops with the falling water level until the sealing ring contacts and closes the tank water outlet tube. These valves have proven extremely useful in that they are inherently trouble-free over long periods of use. However, these flapper valves have had at most a minimal control over the volume of water dispensed from the tank, such control as exists being entirely a function of the overall buoyancy of the chamber.
Since water is becoming or has become a resource to be conserved, it is desirable that it not be wasted and, one of the largest wasters of water is the toilet. A toilet flush tank contains different amounts of water depending on its design and the water level therein. However, most such tanks have a full capacity of between 5 and 8 gallons and essentially all of this volume is dispensed each time the toilet is flushed. This is wasteful since experimentally it has been determined that much lower volumes of dispensed water can be used in toilets to dispose of liquid wastes as compared to that needed to effectively dispose of solid wastes. Thus, if were possible to preselect a water action that dispenses, say a half-tank full, it would be possible to reduce the water consumption of the average residential toilet by between 10 and 20 thousand gallons of water per year. Concomitantly, of course, there is an equal reduction in the volume of sewage to be processed with further savings from this as well. However, in toilet tanks having a relatively constant full water level and normal discharge valves such as the prior art flapper valves, it has not been possible to simply select and control the water dispensing action so that either a full tank or a preselected smaller volume are dispensed.